Rivals still face tough task in taking on Google, as they continue to only inch up and down the conScore rankings

Google is hanging onto its dominant share of the search market, while its competitors inch up and down.

Google edged a bit further ahead in January, going from 66.7% of the search market in December to 67%, industry tracker comScore said.

Microsoft Bing increased its market share by 0.2%, just 0.1% less than Google's increase. However, Bing remains far behind its biggest rival, moving from just 16.3% to 16.5% in the same time frame.

Yahoo, the other significant search player slipped by 0.1%, from 12.2% to 12.1% of the market, according to comScore.

The Ask Network, with 2.8% of the market, and AOL, Inc., with 1.7%, round out the top five search services in January.

Bing, which was launched in June of 2009, has held steady with its share of the search market, but has not been able to significantly chip away at Google's dominance.

"This tells me that Google still hasn't been challenged by Microsoft," said Dan Olds, an analyst at Gabriel Consulting Group. "It turns out that search is sticky. People got used to using Google and it became their go-to search engine for all time. Google search is also embedded in all sorts of other Web sites, which gives them even more users."

While Microsoft has been working to gain market share and mindshare in the competitive market, Yahoo CEO Marissa Mayer has made it clear that Yahoo aims to get back in the game.

During Yahoo's fourth-quarter earnings call, Mayer said Yahoo will invest time and money in an effort to make a comeback in the online search business.

"There's a lot more potential here," Mayer said during the call. "Overall, search is a key area of investment for us. All the innovations in search are going to happen at the user interface level going forward. We need to invest in those features, both for desktop and mobile [devices]. I think both ultimately will be key plays for us."

"Yahoo is going to have a very hard time taking back any search share from Google," said Olds. "Microsoft put a lot of time, money, and technology behind Bing and it really hasn't put a dent in Google's share."

Meanwhile, Google last November updated its search results page. The search leader also moved to boost its local business search by buying restaurant review guide publisher Zagat and travel guide publisher Frommer's.

Last summer, Bing started featuring content from Yelp on its search results page. Yelp is an online company that helps people find great restaurants, hotels and stores based on users' opinions.